A variety of information processing terminals including touch panels, such as smartphones, have been developed these days. Generally, a touch panel integrally includes a display device for displaying a display screen and an input device for user input. The touch panel also has a function of detecting a location of a user's touch with his/her finger, a specially provided pen, or the like. The user can give a processing instruction to the information processing terminal by directly touching the display screen displayed on the touch panel.
In addition, there has been developed a technology for inputting characters in a simple manner in the information processing terminal including the touch panel. For example, PTL 1 discloses the following technology. Option character strings a2 are displayed in an option character-string window W2, the option character strings a2 being registered in association with an input character a1 in an unfixed state, and one of the option character strings a2 which is selected by a user is determined as a fixed character string a4.